This study examined the relationship between adherence to domiciliary nebulized therapy and psychological factors; patient attitudes, anxiety, depression, and quality of life. Ninety three patients aged 45-77 yrs with chronic obstructive pulmonary disease (COPD) and using domiciliary nebulizers were recruited from a hospital database. They completed the St George's respiratory questionnaire (SGRQ)-1 and the hospital anxiety and depression scale (HADS) and attended a semistructured interview. Their usual nebulizers were replaced by Dataloggers, which record the date, time and duration of each treatment, to use for 4 weeks. The SGRQ was then repeated (SGRQ-2). Eighty two patients completed the study. Fifty six percent were poorly adherent; taking less than 70% of the dose prescribed (or less than 60% on regimens of > or = 5 times daily). The total scores on the SGRQ-2 were negatively correlated with percentage adherence. Multiple regression analysis showed that the SGRQ-2 total score was associated with percentage adherence, depression score, feeling supported by clinic staff, and patients feeling that they tried to ignore their chest disease. Patients who report poor quality of life are more likely to be depressed, feel unsupported by clinic staff and be poorly adherent to treatment. Increased levels of clinic support, with the addition of psychological treatments, may be of benefit to some patients with chronic obstructive pulmonary disease.